1. Field of Invention
The present invention relates to a print-controlling method for a printer and a print-controlling device for a printer, which have high-speed and high-quality printing properties when the horizontal and/or vertical resolution of the data to be printed is different from that which is performed by the printer.
2. Description of Related Art
A case in a computer system is considered in which a print-data forming unit outputs binary image data and a printer driver receives and processes the data for outputting to a printer (herein, for example, an impact printer) as print data. In this case, the print-data forming unit outputs only a binary image in which the horizontal resolution and the vertical resolution are the same. However, the printer cannot always print print-data having the same horizontal and vertical resolutions. Therefore, generally a printer performs printing only with the resolutions which can be processed by the printer, or else, depending on the system, those data cannot be printed.
Methods for coping with the case in which the resolution of the print-data differs from that which can be processed by the printer are known, in which a resolution conversion is performed, and the resolution of original multiple-value data is converted into that which is processed by the printer by a method called scaling, i.e., by forming required pixels by a method such as interpolation.
However, a problem is found in that these methods generally include complex processes, which increase the load on a CPU and the processing time. Another one of several problems is that large storage regions are required for the processing.
Another problem is that known methods cannot generally be applied, as they are, to a system for processing binary print data; when binary print data are processed, high quality interpolation cannot be obtained in the binary data, whereby a high-quality printed image cannot be obtained.